Shell-and-tube heat exchangers often employ baffles for directing fluid through the shell in a tortuous path across the tubes. The baffles include holes through which the tubes extend, thereby enabling the baffles to traverse the tubes. It is important to seal any radial clearance that may exist between the holes and the tubes to prevent fluid from bypassing the baffle.
Seals currently being used rely on radial interference to provide a compressive sealing force between the tubes and the holes. Although these seals may be effective, the same compressive forces make it difficult to insert the tubes through the holes at assembly and may even damage delicate heat transfer fins extending from the tubes. In addition, a lack of radial clearance between the tubes and the holes provides no tolerance for radial misalignment.
Therefore, an object of the invention is to provide a pressure actuated seal whose radial sealing force increases in response to an increase in a fluid pressure differential across the baffle.
Another object of the invention is to provide a seal that accommodates concentric misalignment of the tubes with respect to the baffle's holes.
Another object is to provide a baffle that offers its tubes rigid support once the baffle seals have deflected beyond a certain point.
Yet another object is to provide a seal that exerts a significantly lower radial sealing force during assembly than during operation which reduces the axial forces and minimizes damage to delicate tube fins when the tube is inserted through the baffle holes.
A further object is to provide a baffle made of a unitary piece of plastic and having integral tube seals.
A still further object is to provide a baffle having seals that accept tubes with a smooth land portion having an outer diameter that can range from less than to greater than an outer diameter of the tube's heat transfer fins.
These and other objects of the invention will be apparent from the Description of the Preferred Embodiment which follows hereinbelow and the attached drawings.